Current methods allow the creation of antibody repertoires of paired heavy and light chain sequences having identification regions (i.e., barcodes) and originating from single cells. See, e.g., PCT/US2012/000221 (filed Apr. 27, 2012) and PCT/US2012/053698 (filed Sep. 4, 2012), each of which is herein incorporated by reference in its entirety for all purposes. Typically phylogenetic trees generated using these methods can represent over a thousand paired antibodies with considerable diversity. Even where source cells are antigen-sorted it is not necessarily clear which members of the repertoire are capable of interacting with a given antigen, to which epitopes within an antigen, and with what degree of affinity. One approach toward interrogating antibody binding characteristics for individual members within the repertoire is to “cherry-pick” specific members and have the antibodies expressed in a variety of eukaryotic expression systems. While this method can produce functional antibodies it is generally considered inefficient for several reasons: First, antigen specificity typically cannot always be determined a priori from a protein sequence; second, large numbers of antibodies would typically need to be tested to ensure adequate coverage of the repertoire; third, in-vitro production of individual antibodies can be time consuming and expensive, particularly considering the number of antibodies that would usually need to be tested.
Typical antibody display strategies include combinatorial libraries in which variable domains from heavy and light chains from unpaired cDNA repertoires are paired in a random fashion. This blind, shotgun approach to H+L pairing uses the construction of libraries with complexities that can exceed 109 and pose technical challenges when trying to reach the maximum efficiencies necessary to create such a library.